This invention relates in general to apparatus for securing doors, and more particularly to an exit fixture for retaining a door bolt of a door lock in a retracted condition.
The exterior doors of some buildings are opened and closed many times each day, at least during business hours. For reasons of safety, these doors always open outwardly and are equipped with exit fixtures operable from the inside faces of such doors to retract the lock bolts. The typical exit fixture normally has a bar or paddle which is positioned slightly away from the inside face of the door and when pressed toward the door retracts the latch bolt. Thus, anyone pressed against the door in a panic situation will depress the cross bar or paddle and cause the door to swing open.
Since exit fixtures of the foregoing nature tend to wear out quite rapidly when installed on high use doors such as the exterior doors of schools and many public buildings, some of these exit fixtures are provided with dogging mechanisms for retaining the cross bar in a depressed condition and the latch bolt retracted. In that case, the door opens when merely pushed or pulled outwardly. A dogging mechanism of this nature is usually nothing more than a set screw which, when tightened, bears against one of the operating parts of the exit fixture such as the pivot arm to which the cross bar is connected, and thereby secures the arm and cross bar in a depressed condition. Setting and releasing these dogging mechanisms is a time consuming procedure and requires the presence of custodial personnel at the doors. Moreover, there is always the possibility that custodial personnel will forget to release the dogging mechanism on one of the doors after business hours, thereby permitting unauthorized entry into the building.
Heretofore attempts have been made to remotely control exit fixtures with electrically operated devices such as solenoids and motors, but the springs which hold the cross bar out are usually quite strong and to compress them requires considerable electrical energy. Indeed, the amount of energy required to compress such springs demands voltages and currents far in excess of that permitted in doors by most electrical codes.